This research project on Vitamin B6 model systems is being extended to the study of several problems thought to be significant. The kinetics and mechanisms of the dissociation of protons from the beta- positions of Schiff bases of pyridoxal and alpha amino acids will be determined. This information should provide a new approach to the mechanism of elimination of electronegative groups in the gamma positions of alpha amino acids. Nmr and optical rotatory dispersion studies of isomerism of metal chelates of Schiff bases of pyridoxal and optically active alpha amino acids should provide the basis for a better understanding of interrelated reactions such as racemization and transamination. Vitamin B6- and metal ion-catalyzed decarboxylation reactions will be investigated by nmr and other techniques capable of determining the formation and decay of significant reaction intermediates. Rates of alpha proton exchange, racemization, and transamination will be extended to provide further information on the relationship of these reactions to the beta-elimination of electronegative groups. In addition the on-going studies of the kinetics of the threonine aldolase model reaction is expected to lead to interesting mechanistic information that may be applicable to the enzymic reaction.